The solubility product constant K sp for lead iodide is 1.40 in water at 30°C. Calculate the molar solubility of lead iodide in water at this temperature.
a) 1.87 x 10⁻³ M
b) 2.48 x 10⁻³ M
c) 4.20 x 10⁻⁴ M
d) 5.10 x 10⁻⁵ M